Re: Linux 2.6 nanosecond time stamp weirdness breaks GCC build

[Ulrich Weigand]

> 
> On Thu, 1 Apr 2004 15:39:23 -0500
> Daniel Jacobowitz <dan@xxxxxxxxxx> wrote:
> > > 
> > 
> > (I haven't tested anything but...) why should this fix it?  Ulrich's
> > problem happens when the .o file is flushed from the cache, and then
> > stat'd; it now appears to be older than the .c file.  With a change to
> > round up instead, if the .c file is flushed from the cache before the
> > .o, the .c will still suddenly appear to be newer than the .o.
> 
> That is what he wants I think. It's logically just like taking a bit longer. 

Not really.  I have two files generated in sequence:

  .c at 08:12:23.1
  .o at 08:12:23.2

As long as the .o stays more recent than the .c, everything is fine.
With the current code, this breaks if the .o file is flushed and
re-read, while the .c file stays in cache:

  .c at 08:12:23.1
  .o at 08:12:23.0  (oops, suddenly in need of rebuild)

With your suggested change, it will break if the .c file is flushed
while the .o file stays in cache (as Daniel pointed out):

  .c at 08:12:24.0
  .o at 08:12:23.1  (oops, suddenly in need of rebuild)

Both lead to the same type of problem.

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  weigand@xxxxxxxxxxxxxxxxxxxxxxxxxx
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/